Suddenly can't send e-mails

Suddenly I can’t send e-mails - they just sit in the Outbox. I can receive ok.
I last sent an e-mail from phone on 4/7 and haven’t changed any settings.
Any ideas?

Update - I have tried deleting the account and setting it up again. All settings appear to be correct but still won’t send.When I click on the Send icon it says “Sending message” but it sits in the Outbox. When I open it again it says “Draft” at the top.

This is a real problem as I sometimes need to reply to clients when I’m out and about. O2 have confirmed I am using the correct Outgoing server details.

I’m assuming you’ve since sent the e-mails via an other device - have you removed them from the Outbox (or were they removed when you removed the account)? It could be that one of the messages gets rejected by the outgoing mail server, and the app keeps on trying to resend that specific message before moving on to others.

Also, depending on the app you’re using, try forcing the outbox to send mail (in the Gmail app it happens if you swipe down).

Not sure what else can cause a sudden change in functionality without changing anything (where ‘anything’ includes updates to security apps, changes background data handling, etc).

Yes, I can send from iPad and PC and I have tried removing the messages from Outbox. I’m using the Email app that came with the phone. I certainly haven’t deliberately changed anything. I installed the new update recently but the problem existed prior to that.

Did you try cleaning the cache of the app? To do this, go to Settings > Apps > All Apps, scroll down to your e-mail app and delete cache. Sometimes this helps in cases where an app “suddenly” is not working properly anymore.

The swiping down in the Outbox didn’t work and neither did clearing the cache unfortunately.

Hi Andrea,

I have encountered problems with the internal Google mail client too since some days which seems to correspond to an update of the email app. In my case the error was a battery draining sync loop of the exchange service. My solution was not only to delete the mail account but even delete all app related data and caches in the App-Info menu. In my case I did this for all mail-, contact- and calendar-related apps.

Another hint: Do you use the right Port / Security-Settings for outgoing messages? In my case (private account GMX) it is “587” and “STARTTLS (accept all certs)”.

I checked with O2 and they have confirmed my Outgoing server details are correct and these haven’t changed.

What are the consequences of deleting Email app data - I clicked on this and it warned me that it’s permanent and will delete all files, settings, accounts, databases etc


all your E-mail settings AND e-mails will be deleted.

At least the ones stored on the phone. If you have a copy of them on the server, it shouldn’t remove those. Adding the account later will then download the messages again.

Ok, I have now cleared the cache and the data and no change… at a loss!

Did you try my above suggested Port / Security settings?
Have you checked out the right server name for outgoing mails?

Look also here:

Try a “real” e-mail-client: K9Mail.

Those setting are not accepted by my phone. I found an English equivalent of the page you sent the link for and it says to enter what I already have.
port 25
Security none

I also had an online chat with O2 who confirmed I am using the correct settings. They worked fine until recently - I last sent an email on 4/7/16.

As far as I know smtp port 25 without security is no longer accepted by mailproviders. Perhaps your provider has switched some days ago to the above mentioned security based settings without informing their hotliners. Did you try them?
(see also here

Hi, Yes I did try them - they were not accepted. If I change the port to 587 I get the message “Couldn’t finish. Couldn’t open connection to server”

Are you sure you use those settings for outgoing mails:

"your smtpserver"
port: 587
security: STARTTLS or STARTTLS (accept all certs) -> you may try out
login: yes
user: xxxxxx
password: xxxxxxx

Yes definitely Outgoing. I have never entered a User name and password. Is this my O2 user name or my email address?

It is usually the same setting as of the incoming POP3 Server (which seems to work as you say).

In my case (GMX) its my email address and password.